Guessing his superiors at DOGE don't like anyone countering their claims that all of government is irredeemably inefficient and corrupt, as the only thing he said was that he found the VA to be run quite well, and the VA's staff to be competent and motivated.
Saying, as a government employee, that “Hey, the systems, processes, and people at the VA are pretty okay” is not discussing the ‘private details’ of his employees in any way that could be considered inappropriate.
It’s not like he revealed details from private DOGE strategy meetings or discussions.